METABOLITE EFFECTS ON GROUP 111 AND IV MUSCLE AFFERENTS

代谢物对 111 组和 IV 组肌肉传入的影响

基本信息

批准号：
2216695
负责人：
Marc Peter Kaufman
金额：
$ 15.62万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
1987
资助国家：
美国
起止时间：
1987-07-01 至 1995-06-30
项目状态：
已结题

项目摘要

The proposed experiments have two goals. The first goal is to identify the stimulus to the group III and IV afferents whose activation by static muscular contraction signals the central nervous system that blood supply and demand in a working muscle are not properly matched. These afferents will be identified by showing that they respond more to and ischemic static contraction than to a freely perfused contraction, even though both types of contraction than to an ischemic static contraction than to a freely perfused contraction, even though both types of contraction develop the same tension. The hypothesis to be tested is that lactic acid infusion and hypoxemia stimulate group III and IV afferents sensing a mismatch between blood supply and demand in the working muscle, but have no effect on the discharge of afferents not sensing this mismatch. The second hypothesis to be tested that dichloracetate, which attenuates lactic acid production by skeletal muscle, decreases the responses to contraction of afferents not sensing this mismatch. These experiments will be performed in unanesthetized decerebrate cats. Afferent impulse activity arising from the triceps surae muscles will be recorded from the dorsal roots. The second goal is to demonstrate in decorticate unanesthetized cats that group III and IV hindlimb muscle afferents are stimulated by true "true dynamic exercise", induced by activation of the subthalamic locomotor region. Stimulation of this region is known to cause a discharge pattern in alpha motoneurons that is identical to that evoked by dynamic exercise. The effect of ischemia, induced by occlusion of the arterial blood supply to the working muscle, on the afferents' response to dynamic exercise will be examined. In addition, the effect of infusing lactic acid on the afferents' response to dynamic exercise will be examined. The hypothesis to be tested is that true dynamic exercise stimulates group III afferents by mechanical means and group IV afferents are stimulated by exercise, these experiments may shed new light on the puzzling question as to the nature of the metabolic stimulus causing these afferents to signal the central nervous system that blood supply and demand in a contracting muscle are mismatched

拟议的实验有两个目标。第一个目标是确定刺激III和IV的传入，它们的静态激活肌肉收缩信号表明中枢神经系统表明血液供应工作肌肉中的需求不正确。这些传入通过表明他们对他们的反应更多和缺血性静态来确定收缩而不是自由灌注收缩，即使两种类型收缩比缺血性静态收缩，而不是自由灌注收缩，即使两种收缩发展同样的张力。要检验的假设是乳酸输注和低氧血症刺激III组和IV组的传入，感知工作肌肉的血液供应和需求，但对放电的传入不感应这种不匹配。第二个假设可以测试二氯乙酸，通过骨骼肌减少对传入的收缩的反应感觉这种不匹配。这些实验将在未经麻醉的杂交猫。传入的冲动活动是由三头肌肌肉将记录在背根。这第二个目标是在剥离一组的一组猫中证明 III和IV Hindimb肌肉传入被真实动态刺激锻炼”，是由丘脑下运动区域激活引起的。已知该区域的刺激在α中引起放电模式与动态运动相同的运动神经元。这缺血的作用，由动脉血液供应阻塞引起工作肌肉，关于传入者对动态锻炼的反应将是检查。另外，注入乳酸对传入者对动态运动的反应将进行检查。假设要测试的是，真正的动态运动刺激了第三组传入通过机械手段和IV组的传入，通过锻炼刺激这些实验可能会对令人困惑的问题发明新的启示代谢刺激的性质，导致这些传入发出信号中枢神经系统，肌肉中血液供应和需求不匹配